1. Field of the Invention
This invention relates to a new method of imparting antibacterial activity to textiles made of cellulosic fibers, polyester fibers or blends of cellulose with polyester.
2. Description of the Prior Art
Although many types of antibacterial agents have previously been applied to cellulosic and non-cellulosic textiles, the resulting textile materials have generally been deficient in certain properties essential to successful commercial use. Seldom have the products possessed a combination of strong activity against undesirable species of bacteria, together with the necessary durability to repeated laundering. In many instances, previous antibacterial agents have produced undesired physiological side effects on contact with human skin or exposed tissue, or they adversely affected the color, suppleness, softness, and absorbency of the textile. In addition, such agents have usually been expensive to manufacture. Various types of antibacterials previously studied for textile applications have been described by Gagliardi, American Dyestuff Reporter 51 [2] P49-P58 (1962).
It has been known for many years that hydrogen peroxide is a safe and effective topical and oral antiseptic and disinfectant when used in dilute aqueous solution, and it can be used to cleanse open wounds. By itself, it has no substantivity for cellulosic or polyester materials, and is removed in a single washing from yarns or fabrics to which it is applied.
Recently, however, hydrogen peroxide has been shown to form colorless, water-insoluble complexes with zirconyl acetate, and these complexes can be formed in situ as durable deposits on cellulosic textiles, thereby imparting considerable antibacterial activity (Vigo et al, Textile Chemist and Colorist 9 [4] 77-80 (1977); Welch et al, co-pending U.S. patent application, Ser. No. 787,177 filed Apr. 12, 1977). The antibacterial activity of the treated textiles appears to be due to a slow, controlled release of hydrogen peroxide as the effective antibacterial agent. This peroxide release at the textile surface appears to result from the slow reaction of zirconyl acetate-hydrogen peroxide complexes with the regain moisture present in cellulosic fibers of the textile at equilibrium with air at ordinary humidity. In order to obtain even a peroxide content of 0.30%-0.35% in treated fabric, a very high concentration of zirconyl acetate had to be applied, and this led to fabric weight gains of 12%-16%. Such high fabric loadings increased the stiffness, caused a somewhat harsh feel, and decreased the wettability and absorbency of the fabric to an undesirable extent.
It is also well known that a simple, insoluble peroxide of zinc having the formula ZnO.sub.2 can be prepared by adding solid zinc oxide to a solution of hydrogen peroxide containing small concentrations of mineral acid. The product forms as a granular solid (Wood and Clennett, U.S. Pat. No. 2,563,442). A similar product has been made by treating the basic carbonate of zinc in solid form with concentrated hydrogen peroxide (Laporte Chemicals Ltd., French Pat. No. 1,524,638).